SONY WA-3000 Speaker Doesn't Cut when Headphones plugged in...

[cpt.shotwell]

I imagine this is a long shot without the service manual (which I can't find) but I'm wondering where i need to solder a jumper wire to and from in order for the internal speaker to cut out when headphones are plugged in. when i first opened this up to repair there was a loose wire but like a dummy i forgot to document where it was. i imagine it starts over on the upper left side of this shot, where the headphone jack is... anyways any insight is appreciated!